git: kernel - u4b - Implement doorbell
dillon at crater.dragonflybsd.org
Fri Jan 10 12:07:25 PST 2014
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date: Fri Jan 10 12:03:43 2014 -0800
kernel - u4b - Implement doorbell
* Implement the doorbell properly.
* Use the doorbell to clear the previous transfer when reusing a transfer.
This is a horribly inefficient hack but it's better than blowing up the
(This is in addition to the xfer freeing fifo hack)
* We also seem to need to ring the doorbell when queueing transfers. This
should not be necessary.
* Enable ASP. This allows qTD bursts, making high speed busses more
* NOTE: There are still problems with umass. With some USB sticks,
writing to the stick causes the cpu to stall for very long
periods of time. It is shown as 'interrupt' overhead but insofar
as I can tell it's actually the controller stalling the memory
bus for reasons unknown.
This does not happen with e.g. a SATA SSD connected through a USB
Summary of changes:
sys/bus/u4b/controller/ehci.c | 117 +++++++++++++++++++++++++++++++++++-------
sys/bus/u4b/controller/ehci.h | 4 +-
sys/bus/u4b/usb_core.h | 3 ++
sys/bus/u4b/usb_transfer.c | 2 +-
4 files changed, 105 insertions(+), 21 deletions(-)
DragonFly BSD source repository
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